Electrical fuse.



1%. 794,985. PATENTED JULY 18, 1905.

F. G. JONES.

ELECTRICAL FUSE.

APPLICATION FILED NOV. 17, 1904.

Han: Lfones Ewen/Z797. AVA/@A as w iz'nesseski 253m) 41 /@M Patented July 18, 1905.

UNITED STATES PATENT ()FFICE.

FRANK Gr. JONES, OF CHICAGO, ILLINOIS.

ELECTRICAL FUSE.

SPECIFICATION forming part of Letters Patent No. 794,985, dated July 18, 1905.

Application filed November 17, 1904. Serial No. 233,12 L.

To all whom it may concern.-

Be it known that I, FRANK G. J ONES, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented a new and useful 1mprovement in Electrical Fuses, of which the following is a specification.

My invention relates to an improvement in electrical fuses, and has for its object the betterment of that type of fuse in which the fusible wire, on account of the small carrying capacity desired, is of such small diameter as to render it fragile, and therefore making additional. mechanical support necessary. Fusewires of this type are often mounted upon a thin sheet of mica or other suitable insulating material, the fuse itself being attached to the mica by shellac or by other suitable means. At each end of the mica strip which is so employed to form a support for the wire is attached a metallic terminal, usually of copper or tin-foil, to which each end of the fusewire is attached. These terminals afford a ready means for including the fuse-wire in the electrical circuit that it is desired to protect, suitable stationary clips'or binding-posts being provided for the convenient reception of the mica strip with its metallic terminals. This type of fuse-wire, which is commonly known in the art as the mica fuse, is subject to disadvantages, one of which is the fact that the frail wire is inadequately protected from mechanical injury and is liable to be broken either during its insertion into the circuit or thereafter by causes other than the passage of too great a current through it. Again, considerable difficulty has been experienced in the use of the type of fuse above referred to in securing the proper contact between the fuse-wire itself and the metallic terminals at the end of the mica strip. This is due to the fact that the electrical contact at 'the joint between the fuse-wire proper and tact and at another no contact at all or a poor.

one, so that the fuse may upon being tested appear to be without fault and yet when put into practice fail to accomplish its mission. Where the metallic terminals upon the strip are of copper and the fuse-wire is secured thereto by minute particles of solder, which construction is extensively practiced in fuses now made, an additional fault often exists due to the fact that in slipping the fuse into the holder the friction of the holder against the fuse frequently loosens the fuse, and thus renders it inoperative. Thus, although the fuse may have been tested before applying it to the circuit, it is rendered imperfect, and the defect would appear only by its failure to perform its functions. Still another defect exists in the type of fuse referred to,

owing to the fact that the fuse is attached by shellac or other adhesive which becomes hard, thus bringing about the liability to break the fuse when the mica strip which carries it is bent. It is to the remedying of all of these difficulties that my invention is directed.

In theaocompanying drawings, which'illustrate my invention, Figure 1 is a side view of a type of fuse that is commonly used in the art. Fig. 2 is an end view thereof. Figs. 3 and 4: are respectively side and end elevations of my improved fuse during process of assembling, and Figs. 5 and 6 are similar views of the completed structure.

In all of the figures showing end views of the fuse the thickness of the material is much exaggerated in order to facilitate their illustration, and this fact will be easily understood by those skilled in the art.

In Fig. 1, l is a mica strip supporting two terminals 2 and 3, which are in this case formed of thin copper ribbon bent around the ends of the strip 1, as shown. 4 is a fuse-wire extending along the mica strip between the terminals 2 and 3, this being secured to the latter by bits of solder, as shown at 5 and 6, and to the mica strip itself by a coating of shellac or other similar non-conducting adhesive.

In Figs. 3 and 4- is shown a partly-completed fuse manufactured in accordance with, my present invention. In this the mica strip 7 is surrounded at each end by copper ribbons 8 and 9, the construction in this case being similar to that shown in Figs. 1 and 2, except that the copper ribbons are longer-in fact, being made of sufiicient length to pass twice around the strip. After the strips of copper have been applied, as shown in Figs. 3 and 4, the fuse-wire 10 is applied and secured at its ends to the copper strips by drops of solder 11 and 12. In doing this the fuse is not stretched tightly between its supports, but is left rather loose, as shown, and no shellac or other adhesive is applied to bind the free portion of the wire to the mica. After securing the fuse as thus stated a separate piece of mica 13 of the same size and shape as the piece 7 is laid over the fuse-wire, so that the wire is thus sandwiched between them. After this the strips of copper 8 and 9 are bent down over this added piece of mica 13 and around to the other side of the strip 7, thus binding the whole firmly together. The copper strip is pressed by any suitable means into close contact with the mica strips, so that the combined fuse will not be of undue thickness and also so as to prevent the copper ter minals from moving with respect to the pieces of mica. By these means the various defects spoken of in the first part of this specification are to a large extent remedied. Perfect contact between the fuse and the metallic strips, when once secured by soldering or otherwise, is maintained with far greater permanence than could be secured with the constructions shown in Figs. 1 and 2. This is on account of the mechanical protection afforded by the joint being completely inclosed and, further, because of the fact that a considerable pressure is exerted by the winding of the copper strips completely around the two mica strips, thereby tending to bind the fuse-wire into firm contact with the copper strips, thus maintaining a connection even though the soldering may have been improperly done. The inclosing of the complete fuse between the two mica strips effectively prevents damage due to mechanical causes, and the fact that the fuse is practically free between its ends and not bound to either one or the other of the strips by shellac makes it possible to bend the strip to a considerable extent without causing any tension in the fuse-wire. This construction is also of advantage in the shipping of the fuses, as great care is not necessary to prevent the breakage of the delicate fuse-wire.

\Vhile I have specifically referred to mica as being the material for the insulating-strips and to copper as being the material for the terminals, I do not wish to be limited to these materials, as it is obvious that there are other suitable materials which might be used. Neither do I wish to be limited to a solder connection between the fuse-wire and theterminal strips, as in some constructions it is sufficient to merely clamp the fuse at its end between the mica strip and the metal of the terminals or to adopt other wellknown exped ients.

Having now described my invention, what I claim is- 1. In a fuse for protecting electrical circuits, a pair of insulating-strips, a fuse-wire placed between said strips, and conductingpieces at each end of said strips binding said strips together andv forming terminals for said fuse-wire, substantially as described.

2. In an electric protective device, an insulating strip, a metallic ribbon wrapped around each end of said strip, a fuse-wire secured between said metallic ribbons and alongside said strip, a second insulating-strip so placed as to include said fuse-wire between it and said first insulating-strip, said metallic ribbons binding said second strip to said first, substantially as described.

3. In a protective device for electric circuits, a pair of insulating-strips, a fuse-wire between said strips, a pair of metallic ribbons forming terminals for said fuse-wire, said ribbons extending between said strips and then around both of them, thus binding said strips together, substantially as described.

Signed by me at Chicago, county of Cook, and State of Illinois, in the presence of two witnesses.

FRANK G. JONES.

\Vitnesses: V

KEMrstrnn B. MILLER, EVA A. GAnLocK. 

